package com.snowcattle.game.common.util;


import org.apache.log4j.Logger;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;


/**
 * This program generates a AES key, retrieves its raw bytes, and then
 * reinstantiates a AES key from the key bytes. The reinstantiated key is used
 * to initialize a AES cipher for encryption and decryption.
 */
public class AES {

    private static final String AES = "AES";
    private static final String CRYPT_KEY = "hsylgwk-20120101";

    private static Logger logger = Logger.getLogger(AES.class);

    /**
     * 加密
     *
     * @param encryptStr
     * @return
     */
    public static byte[] encrypt(byte[] src, String key) throws Exception {
        Cipher cipher = Cipher.getInstance(AES);
        SecretKeySpec securekey = new SecretKeySpec(key.getBytes(), AES);
        cipher.init(Cipher.ENCRYPT_MODE, securekey);// 设置密钥和加密形式
        return cipher.doFinal(src);
    }

    /**
     * 解密
     *
     * @param decryptStr
     * @return
     * @throws Exception
     */
    public static byte[] decrypt(byte[] src, String key) throws Exception {
        Cipher cipher = Cipher.getInstance(AES);
        SecretKeySpec securekey = new SecretKeySpec(key.getBytes(), AES);// 设置加密Key
        cipher.init(Cipher.DECRYPT_MODE, securekey);// 设置密钥和解密形式
        return cipher.doFinal(src);
    }

    /**
     * 二行制转十六进制字符串
     *
     * @param b
     * @return
     */
    public static String byte2hex(byte[] b) {
        String hs = "";
        String stmp = "";
        for (int n = 0; n < b.length; n++) {
            stmp = (Integer.toHexString(b[n] & 0XFF));
            if (stmp.length() == 1)
                hs = hs + "0" + stmp;
            else
                hs = hs + stmp;
        }
        return hs.toUpperCase();
    }

    public static byte[] hex2byte(byte[] b) {
        if ((b.length % 2) != 0)
            throw new IllegalArgumentException("长度不是偶数");
        byte[] b2 = new byte[b.length / 2];
        for (int n = 0; n < b.length; n += 2) {
            String item = new String(b, n, 2);
            b2[n / 2] = (byte) Integer.parseInt(item, 16);
        }
        return b2;
    }

    /**
     * 解密
     *
     * @param data
     * @return
     * @throws Exception
     */
    public final static String decrypt(String data) {
        return decrypt(data, CRYPT_KEY);
    }

    public final static String decrypt(String data, String pass) {
        if (data == null || data.isEmpty()) {
            return "";
        }
        try {
            return new String(decrypt(hex2byte(data.getBytes()), pass));
        } catch (Exception e) {
            logger.error("AES-ENCRYPT:" + data, e);
        }
        return data;
    }

    /**
     * 加密
     *
     * @param data
     * @return
     * @throws Exception
     */
    public final static String encrypt(String data) {
        return encrypt(data, CRYPT_KEY);
    }

    public final static String encrypt(String data, String pass) {
        if (data == null) {
            data = "";
        }
        try {
            return byte2hex(encrypt(data.getBytes(), pass));
        } catch (Exception e) {
            logger.error("AES-ENCRYPT" + data, e);
        }
        return "";
    }

}